Production of cyclo-olefinic hydrocarbons and aromatic hydrocarbons



Patented Aug. 27, 1946 PRODUCTION OF CYCLO-OIJEFI NIC HYDRO- CARBONS AND AROMA'TIC HYDROCAR- 'BONS Herman Pines and Vladimir N. Ipatieff, -Cl'licago,

111., assignors to Universal Oil Products Company, Chicago, Ill, a corporation of Delaware NoDrawing. ApplicationDecember 15, 1944, Serial No. 568,391

8 Claims. (01. zco cesl This invention relates to a process for producing cyclic hydrocarbons. More specifically, the invention-relates 'toa process forproducin cycloolefins by condensing a lycol of at least 4 carbon atoms iper'molecule with-a monohydric alcohol.

An object of this invention is the condensation of an aliphatic monohydric alcohol with a glycol containing at least 4 carbon atoms per molecule.

Another object of this invention is the production of a cyclohexene hydrocarbon by condensing an 'alkanol with :a glycol containing at least 4 carbon atomsper molecule.

A further object of this invention is the production of a cyclohexene hydrocarbon by the condensation of a glycol containingat least 4 carbon atoms per molecule with an alcohol selected from the group consisting of primary and secondary alkanols.

A still further object of this invention is the production of 1,3,5-trimethylcyclohexene by condensing 2-methyl-2;4-.p.en;tanediol with a, propyl alcohol.

One specific embodiment of this invention relates to a process for producing a cyclo-olefin which comprises condensing an alkanol and a glycol having at least 4 carbon atoms per molecule in the presence of an acid-acting catalyst at a temperature of from about 150 to about 400 C.

A further embodiment of this invention relates to a process for producing a benzene hydrocarbon which comprises condensing an alkanol and a glycol containing at least 4 carbon atoms per molecule to produce a cyclohexene hydrocarbon, hydrogenating said cyclohexene hydrocarbon to a cyclohexane hydrocarbon, dehydrogenating said cyclohexane hydrocarbon to a benzene hydrocarbon and hydrogen, and utilizing at least a portion of said hydrogen in the hydrogenation of said cyclohexene hydrocarbon.

Cyclohexene and difierent alkyl cyclohexene hydrocarbons which are obtainable by the process of our invention may be hydrogenated to cyclohexane hydrocarbons, or be dehydrogenated to benzene and alkyl benzene hydrocarbons.

By the term condensation used in this specification and. in the claims, we mean the chemical combination of a dih'ydric alcohol having at least 4 carbon atoms per molecule and a monohydric alcohol accompanied by thesplitting out i of water. Thus, we have found that 2-methyl- 2,4-pentanediol and isopropyl alcohol react at an elevated temperature to produce 1,3,5-trimethylcyclohexene and water as the principal condensation products.

Glycols, alsoknow-n as dihydric alcohols, utilizable in our process contain at least 4 carbon atoms :per molecule and have two hydroxyl groups, these groups being preferable in the beta, gamma, and delta positions to each other. Also cyclic glycols such :as 13- and 1,4-cyclohexanediols are utilizable in our process. Olefinic alcohols or partially dehydrated glycols such as '2- methylpentene-1-o1-4, are also useful raw materials for our cjondensati n process.

Monohydric alcohols utilizable also as starting materials in the process of our invention are generally those :of the aliphatic series and preferably are saturated aliphatic carbinols which are also known as alkanols. Alkanols which do not contain :a quaternary carbon atom are particularly 'desirablecfor condensationwith a glycol as herein set forth as alkanols which contain a quaternary carbon atom sometimes yield a substantial proportion of a teritary olefin rather than the condensation product desired.

Although our IJI'OOESS is sometimes carried out in the absence of. an added catalyst at suitable operating conditions of temperature and pressure, we prefer to utilize catalytic materials to assist in the condensation of a glycol containing at least 4 carbon atoms per molecule and an alcohol, preferably an alkanol, and more particularly an alkanol which does not contain a quaternary carbon atom. Catalysts utilizable in our process are acid-actin materials and comprise activated alumina, hydrated silica, acid-treated clays; synthetically prepared composites comprising silica-alumina, silica-alumina-zirconia, alumina-zirconia, silica-alumina-thoria; acids such as hydrochloric acid, hydrobromic acid, a phosphoric acid, sulfuric acid, a, heteropoly acid as phosphotungstic 0r posphomolybdic acid, etc; and also aqueous solutions of hydrolyzable salts such as ferric chloride, magnesium chloride, zinc chloride, ammonium chloride, magnesium acid phosphate, sodium acid sulfate, etc. These materials which we may employ as catalysts in our process are acid-acting in the sense that an aqueous solution or suspension thereof in Water has a pH below 7.

Our process may be carried out using either batch or continuous types of operation, although the latter is preferable. out at a temperature of from about to about 400 0., but preferably at a temperature of from about to about 300 C. The process is preferably efiected at a pressure of about 1 atmosphere or higher and is generally not in excess of about 100 atmospheres.

The process is carried 7 The following example is given to illustrate the character of results obtainable by the process of our invention, although the example is not introduced with the intention of restricting unduly the broad scope of the invention.

1.3 molecular proportions of isopropyl alcohol and 1 molecular proportion of 2-methyl-2,4-pentanediol are commingled and charged to an autoclave containing a solution of ferric chloride in water. The aqueous solution utilized contains about by weight of ferric chloride dissolved in water and the volume of this solution is approximately equal to that of the mixture of glycol and alcohol introduced thereto. The charged autoclave is then heated at about 250 C. for a time of 2-4 hours. After cooling, the reaction mixture contains a hydrocarbon layer comprising essentially 1,3,5-trimethylcyclohexene which is produced in a yield of.about 30% of the theoretical. Trimethylcyclohexene so formed is convertible into mesitylene by hydrogenationand dehydrogenation treatments.

The novelty and utility of the. process of the present invention are evident from the preceding specification and example, although neither section is introduced to limit unduly the broad scope of our invention.

We claim as our invention:

1. A process for producing a cyclo-olefinic hydrocarbon which comprises reacting a glycol having at least 4 carbon atoms per molecule and a monohydric alcohol at a suflicient temperature and pressure that condensation of said glycol and monohydric alcohol is the principal reaction of the process.

2. A process for producing a cyclo-olefinic hydrocarbon which comprises reacting a glycol having at least 4 carbon atoms per molecule and an alkanol at a temperature of from about 150 to about 400 C.

3. A process for producing a cyclo-olefinic hydrocarbon which comprises reacting a glycol having at least 4 carbon atoms per molecule and an alkanol at a temperature of from about 150 to about 400 C. and at a pressure of from about 1 to about atmospheres.

4. A process for producing a cyclo-olefinic hydrocarbon which comprises reacting a glycol having at least 4 carbon atoms per molecule and an alkanol in the presence of an acid-actin cat alyst at a temperature of from about to about 400 C.

5. Aprocess for producing a cyclo-olefinic hydrocarbon which comprises reacting a glycol having at least 4 carbon atoms per molecule and an alkanol in the presence of an acid-acting catalyst at a temperature of from about 150 to about 400 C. and at a pressure of from about 1 to about 100 atmospheres.

6. A process for producing a cyclo-olefinic hydrocarbon which comprises reacting a glycol having at least 4 carbon atoms per molecule and an alkanol in the presence of an aqueous solution of a hydrolyzable metal salt at'a'temperature of from about 150 to about 400 C. and at a pressure of from about 1 to about 100 atmospheres.

7. A process for producing a benzene hydrocarbon which comprises condensing an alkanol and a glycol containing at least 4 carbon atoms per molecule to produce a cyclohexene hydrocarbon, hydrogenating said cyclohexene hydrocarbon to a cyclohexane hydrocarbon, dehydrogenating said cyclohexane' hydrocarbon to a'benzene hydrocarbon and hydrogen and utilizing at least a portion of said hydrogen in the condensation of said cyclohexene hydrocarbon.

8. A process for producing a benzene hydrocarbon which comprises reacting analkanol and a glycol containing at least 4 carbon atoms per molecule to produce a cyclohexene hydrocarbon and dehydrogenating said cyclohexene hydrocarbon to a benzene hydrocarbon.

HERMAN PINES. VLADIMIR N. IPATIEFF. 

